Escapement.



6.1. HEDBERG.

ESCAPEMENT.

APPLICATION FILED SEPT. H. 1916.

Patented Dec. 30,1919.

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awe away "UNITED srnrns PATENT orrion GEOBG JOHNSSQN I-IEDBERG, OF STOCKEOLM, SWEDEN, A$SIGNOR OF ONE-HALF TO ANDERS LINDAI-IL, OF STOCKI-IOLM, SVJEDEN.

ESCAPEMENT. I

Specification of Letters Patent.

Application filed September 11, 1916. Serial No. 119,451.

To all whom it may concern:

Be it known that I, Gnone JoHNssoN HED- nnno, a subject of the King of Sweden, and resident of Stockholm, in the Kingdom of Sweden, have invented certain new and useful Improvements in Escapements, of which the following is a specification, reference being made to the accompanying drawing.

The present invention has for its object to provide an improved escapement for clock works or similar works.

As iswell known, the escapement of a clock work consists of two principal parts, viz: a part rotating intermittently, called the escapement wheel, receiving motion from the source ofpower of the clock work, and an" oscillating part, called the anchor, which due to its oscillation permits the intermittent movement of the escapement wheel, and regulates the rate of such movement. -The anchor is generally connected with a fly or balance wheel, a coil spring regulating the swing of-said wheel, or it is connected with a pendulum. The surfaces of the anchor, which are acted upon by the escapement wheel during the periods of rest and movement, or draw, are hereinafter called rest surfaces, and draw surfaces respectively. These'surfaces are curved according to' certain radii.

The present invention relates to escapements inwhich the anchor spindle crosses, or is perpendicular to, the spindle of the escapement wheel, and it has for its" object to make the device practically insensitive to substantial variations of the motive power, in order to obtain a regular motion. This is attained, according to the present invention by making the active radius of the rest surfaces shorter than the active radius of the draw surfaces.

The annexed drawing shows, by way of example, an escapement constructed according to this invention. Figure 1 is a side view of the same, while Fig. 2 is a sectional view on the line AB of Fig. 1, looking in the direction of the arrow p.

Although the invention is shown as applied to an'escapement having a balance wheel and a coil spring, it may, evidently, also be applied to a pendulum escapement.

On a spindle 1 (hereinafter called the anchor spindle) which as usual carries the balance wheel 2 of the escapement and is acted'upon by the coil spring 3, two

disks are attached at a short distance from each other, viz: an upper disk 4 and a lower disk 5. From these disks extend two arms 6 and 7 and from the free ends of such arm's bars 8 and ,9, sloping toward the lower end of the spindle 1, run in opposite directions in arcs'struok from the'center of the spindle 1 (seeFig. 2). Said disks and bars form the anchor of the escapement and the escapement wheel of the mechanism coiiperates therewith for regulating the rate of movement. In the present case the escapement wheel consists of a so-oalled crown wheel, that is to say a wheel 13 from one side ofwhich there project teeth or pins 10, which successively engage the disks 4 and 5 and the bars 8 and-9 ashereinafter described. The crown wheel is so positioned PatentedDeo. 30, 1919. l

three principal positions, viz: an intermediate position corresponding to no tension in the coil spring 3, and two extreme positions corresponding. to the maximum ten-- sions of the coil spring when said wheel is oscillated first inone direction and then in the other.

Suppose that the balance wheel 2 is rotatingin the direction'of the arrow 20 and that the end of one of the pins 10 is resting upon the upper disk 4:. In the rim of said disk there is a notch 11 of such a size and in such a position that the pin 10, when the disk arrives at its' intermediate position,

moves down through the notch and comes into contact with the upper'barB. On. account of the sloping of this bar a draw now takes place, by which the balance wheel obtains an impulse in the direction just indicated (arrow p and the wheel continues rotating in this direction. after the pin has left the bar 8 and come into contact with the lower disk 5. Owing to increasing re-' sistance of the coil spring 3, the balance wheel 2 finally'stops and then begins rotating, in the direction opposite to that indicated by the arrow 77 The before-men tioned pin lO will continuerestingagainst the disk 5 until a notch 12 in the disk" 5, corresponding to the notch 11 thedisk 4,

arrives opposite the pin, which will be when the intermediate position is again reached. The pin then passes through said notch 12 and acts upon the bottom bar 9 causing a second draw and imparting an impulse to the balance wheel in the direction opposite to that indicated by the arrow 79. When the pin has left the bar 9, the following pin comes into contact wlth the upper side of the disk 4. The balance wheel continues rotating in the direction just mentioned opposite to the arrow 10 until it is again arrested by the coil spring 3 and then it begins to move back again in the d1- rection of the arrow 39 and the operation above described is repeated.

The extreme ends only of the pins 10 touch the disks l and 5 and those parts of'the upper sides'of said disks which are touched by the pins form the above-mentioned rest surfaces, while the above-mentioned draw surfaces are formed by the upper sides of the bars 8 and 9, said sides being engaged by parts of the pins 10 lying nearer the wheel 13.

As will be seen from Fig. 2, the radius of the rest surfaces is comparatively small relatively to the radius of the draw surfaces.

The latter (as well as the former) are shown as being concentric with the axis of the spindle 1 but they may be made eccentric so as to have an increasing or a decreasing radius. The leverage or movement of the draw may thus be either constant or adapted to increase or adapted to decrease. The intensity of the draw may also be regulated by changing the distance of the draw surfaces from the anchor spindle 1 and the slope thereof.

It is of importance, in order to obtain a regular motion of the escapement, that the ends of the rest surfaces and the draw surfaces are displaced in relation to each other in the longitudinal direction of the anchor spindle. If this were not the case, the escapement would stop by itself.

It is also of importance that the notches 11 and 12, and consequently the upper ends of the draw surfaces are in front of the pins 10 exactly at the time when there is no tension in the coil spring 3 (or at the middle position of a pendulum if such is used), so that the apparatus, if run down, will start by itself when subsequently wound up.

It will be noted that the balance wheel can rotate almost an entire revolution with one .of the pins 10 in engagement with one of the rest surfaces and for this reason the balance wheel can, during one oscillation, perform almost two revolutions. This is a considerable advantage of this escapement or the escapement wheel, directly acts upon the oscillating member, or the anchor.

To obtain an accurate measuring of time it is necessary that the rotation of the balance wheel is great so that it is not less than one revolution but it should not, for practical reasons, exceed one revolution and a half. This is obtained in the present escapement by reason of the difference of size of the radii of the draw surfaces and the rest surfaces. In consequence of the radius of the draw surfaces being comparatively large, the supply of motive power during the draw will be comparatively great, while the comparatively small size of the radius of the rest surfaces will result in the braking of the oscillating member, or the anchor being relatively small. A great supply of motive power and a small braking will evidently cause a great amplitude. By giving suitable values to the moment of inertia of the balance wheel, the strength of the coil spring and the radii of the rest and draw surfaces (absolutely as well as relatively) and also to the length, slope and form of the draw surfaces oscillations may be obtained that are always equal as to their amplitude or time. This is obviously of the greatest importance for an accurate measuring of time.

When the draw surfaces are eccentric to the anchor spindle or more broadly speaking, approach or recede therefrom between their ends, there should be a constant relation between the unequal sizes of radii so that an increased or a decreased supply of motive power to the anchor during the draw is accompanied by a braking of the same which is increased or decreased in a corre sponding degree.

The draw parts of the mechanism, that is to say the members forming the draw surof the pins of the escapement wheel exerted on them.

The advantage thus obtained is, among other things, that when an escapement wheel pin 10 acts upon a draw part, the latter will be bent a little, so that the pin passes on to the next rest surface without impingement. When the pin has left the draw part, the latter will recoil and giveway to the pin at the subsequent rotation in the opposite direction of the anchor.

Having now described my invention, what I claim as-new and desire to secure by Letters Patent is:

1. In an escapement, an escapement wheel, an anchor spindle arranged transversely to the axis of said escapement wheel, a disk mounted on said spindle having a peripheral notch and carrying a radially extending arm provided. at its outer end with an inclined foot curved concentric with said disk, a second disk fixed to the spindle and having a peripheral notch and carrying a radially extending arm provided at its outer end with a foot inclined opposite to the foot of the other disk and curved concentric with the second disk, said disks forming rest surfaces and said inclined feet forming draw-surfaces, and means on said escapement wheel for engaging said surfaces, said means engaging the rest surfaces on an effective radius less than the effective radius of the draw-surfaces and being adapted to pass on to the draw-surfaces through said peripheral notches.

2. In an escapement, an escapement wheel having spaced pins extending parallel to the axis of the wheel, an anchor spindle arranged transversely to the axis of the escapement wheel, a disk mounted on the spindle having a peripheral notch and carrying a radially extending arm provided at its outer end with an inclined foot curved concentric with said disk and extending downwardly below said disk, and a second disk fixed to the spindle below the first disk having a peripheral notch and carrying a radially extending arm provided at its outer end with a foot inclined opposite to the foot of the other disk and curved concentric With the second disk, said disks forming rest sur-' faces and said inclined feet forming drawsurfaces, said pins engaging the rest surfaces on an effective radius less than the effective radius of the draw surfaces and being adapted to pass on to the draw surfaces through said peripheral notches.

Stockholm, August 9th, 1916.

In Witness whereof I have hereunto set my hand in presence of two witnesses.

GEORG J OHN SSON HEDBERG.

Witnesses:

H. D. OHLSSON, CARL TH. LUNDHOLM. 

